1. Field of the Invention
The subject invention relates to a system and method of water treatment, and more particularly, to systems and methods of delivering controlled doses of chlorine dioxide or other sanitizing agents into a pressurized water system.
2. Background of the Related Art
Potable water contains various levels of background contaminants such as HPC, pathogenic bacteria and algae, even after municipal treatment. In most instances, chlorine is used to reduce the concentration of such background contaminants. Chlorine and chlorine compounds used for sanitization or disinfection are often removed from water supplies prior to use in drinking water systems, food service beverage systems and ice dispensing equipment. The reasons for removal vary depending on the application or system. For example, the presence of chlorine in the water supply to certain beverage systems may negatively impact a particular quality of the beverage product, such as its taste.
There are also a significant amount of downstream potable water systems that do not use disinfection chemicals. This results in increased levels of microorganisms and biofilm build-up. The build-up increases within dechlorination filters, resin beds, and other finely divided media filters during periods of stagnation. The build-up can be released downstream at high levels causing health concerns, as well as severe off-tastes and odors. Over a prolonged period of time biofilm coats water lines and wetted parts of dispensing equipment, thus compounding the problem.
The concern generated by known high levels of microorganism build-up has caused many in the food service and drinking water industry to periodically sanitize water lines, often reaching the threshold allowable by state or local regulations. Many of the sanitization procedures currently available are difficult to administer, costly, service intensive and use highly toxic chemicals. Some of the chemicals typically used in these procedures include peroxide, chlorine derivatives, muric acid and citric acid. Although the desired sanitizing effect may be achieved by these procedures, they are seldom implemented due to the aforementioned problems.
Chlorine dioxide or other sanitizing agents have also been found to be highly effective as a sanitizer for use in potable water lines. Prior treatment procedures employed a highly concentrated solution of chlorine dioxide or other sanitizing agents, which is formed independently in a remote container and then pumped into the system lines. This solution is allowed to remain in the system lines for extended periods of time while the pressure in the water line is shut off.
One of the primary disadvantages of using chlorine dioxide or other sanitizing agents as a sanitizer according to prior treatment procedures is the economic cost associated with the resulting system downtime since the system being sanitized is unusable during the treatment. Also, due to the toxic nature of the chlorine dioxide or other sanitizing agents solution, a specially trained service technician is often required to remain on-site until the solution is completely flushed out, thus further adding to the financial burden associated with these prior treatment procedures.
The flushing process itself often significantly extends the system downtime of the prior treatment procedures because of a residue left in the system lines by the prolonged static exposure to the chlorine or other sanitizing agents solution. This residue is often difficult to remove, and even low levels of such residue may be considered toxic or noxious, thus requiring the repeated flushing of the system.
It would be beneficial therefore, to provide a system and method for delivering controlled doses of chlorine dioxide or other sanitizing agents into a pressurized water system, which overcomes the deficiencies of the prior art.